Microscope attachment for surveying instruments



g 1,629,373 May 17, 1927- E, w. ARMS MICROSCOPE ATTACHMENT FOR SU VEYING INSTRUMENTS Filed Oct. 20, 1925 2 heets-Sheet l E. W. ARMS May 17.1921.

MICROSCOPE ATTACHMENT FOR SURVEYING INSTRUMENTS Filed Oct/.20, 1925 2 Sheets-Sheet 2,

Fatented May 17,; 1927.

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EDWARD W. ARMS, OF TROY, NEW YORK, ASSIGNOR 'IO & L. E. GURLEY, F TROY,

NEW YORK, A CORPORATION OF NEW YORK.

MICROSCOPE ATTACHMENT FOR sURyEYiNe INSTRUMENTS.

Application filed October 20 1925. Serial No. 63,751.

" ports the microscope always at the correct angle for reading the graduations without errors caused by parallax. The microscope is 'so mounted that it may be focused and the focus, when once satisfactorily adjusted need not be disturbed. The support is so contrived that when the microscope is not needed the arm may be swung beyond the end of. the are and the microscope may then be tipped into the plane of the are. thus materia-lly reducing the over-all dimensions of the instrument and permitting the use of a more compact carrying case.

The invention is shown applied to an alidade in the accompanying drawings, in which Fig. 1 is a perspective view of an alidade showing the microscope applied. In this view the microscope is in position for use;

Fig. 2 is a fragmentary vertical section on the axis of the trunnions of the telescope, showing the microscope in position for use;

Fig. 3 is a fragmentary plan view showing the microscope folded to its inoperative position preparatory to packing the instrument;

Fig. 4c is a fragmentary side elevation showing the parts in the position of 3;

Fig. 5 is a perspective view showing the component parts of the microscope and support partially disassembled.

The ruler is indicated at 11 and this, as usual, carries a circular spirit level 12 and a trough compass 13. Mounted on the ruler 11 is a frame or pedestal 14 and mounted in trunnions on the pedestal 14 is the usual telescope 15 whose eye-piece is shown at 16. The details of the telescope and its mounting need not difier from standard practise and hence will not be described.

One of the axes or trunnions on which the telescope is mounted is shown at 17 2. It carries fixed toit a movable are 18 and has a portion 19 projecting beyond this are (Fig. 2).

The are 18' carries the usual graduations indicated in, the drawings, and

these coact with the index graduations on the plates 20 whichare supported on the Vernier arm 21. The vernier arm 21swings on the axis ortrunnion, 17 and may be adjusted by a tangent screw 34. Such adjustment is made by referenceto' a control level 35 on Vernier arm 21. t

The microscope structure forming the subject of the present invention, andnow about to be described, is for. the purpose of reading accurately the graduations on the are 18. Swiveled on the projecting end 19 of the trunnion or axis 17 is an arm 22. This is recessed on both faces, as clearly indicated in'Figs. 2 and 5. The rear recess receives the projecting part 19 of the trunnion and the frontrecess offers a seat for the spring washer 23. The arm 22 is retained on the trunnion 17 and the spring washer 23 v1s stressed to the extent desired by a knurled screw 24. This. is threaded in the end of the trunnion 17 and has ashoulder 36 which seats against the end of trunnion 17.

An off-set yoke 25 is hinged to the outer forked end of the arm 22 by means of a pin 26. The yoke is formed adjacent the pin 26 with a sharp heel or corner 27 which coacts with a leaf spring 28 to produce a knife hing-e. The leaf spring 28 is held by screws 29. The parts are so constructed that the yoke 25 may be swung on the pivot 26 to either of two positions at approximately 90 from each other, the leaf spring 28 acting to retain the yoke impositively in either of these two positions. The yoke 25 is singularly ofl'set as shown, so that in one position of the yoke the axis of the microscope tube 30 is properly directed toward the graduations on the are 1.8.

The microscope tube 30 is externally threaded and is screwed into a threaded opening in the yoke 25. The yoke 25 is slotted transversely to this opening at 31 and slightly sprung so that a moderate frictional clamping action is exerted on the and 4 so'that it is above oneend oi the arc 18. The yoke 25 is then tilted inward on the pivot 26 toward the telescope. This brings the partsfto the position best, shown in'Fig 3 in which the microscope tube and cye piece are wholly Within the plane of the outer side of'the screw 24 and overlying one endofthe-arc 18.

"It will he observed that "the microscope is adius'tableffor focus, tha't it swings in an arcuate path concentric with the arc 18,

that it ma be swung to any position jrelalie arc and that when not in usc it may be-swu-ng clearofthe arc andfthe microscope may be'tip'ped to a position in which it falls Within the dimensional limits of the alidade prope'iy I Tlhe invention is applicable "to wide variety of instrumentsin su'bstantial'lyjthe {manner above illustrated and described.

'What is claimed is: r

-1. 'The combination of a geometrical instrument including a {graduated are; a '-microscope for reading t-he graduations on said =arc'; an arm pivoted toswing on an axis'subst'antially concentric Withsaid arc; a carrier 'men'i'ber directly supporting sald microscope; and a hinge connection between said carrier and arm arranged to permit said microscope to swing into the space at the-end of said are when not in use.

:2. The 'comhination 'ofaageoinetrical instrumentincludingla graduated arc; a microscope for reading the graduations on. said'arc gan arin p'i'voted-to swing on an axis substantially concentric with said arc; a carrier memberdirectly supporting said microscope; a hinge connection between said carrier and arm arranged to permit saidmicrosc'opesto swing into the space at the end of said are when notim use; and an impositive detent associated with said hinge and arranged to retain said carrier member alternatively 1n the po'sltion last named and in its operative position for reading said gradnations.

3. The combination of a geometrical instrument including a graduated arc; a microscope'for, reading the gra'duations on said are; .a threaded tubular mount for. said microscope; an arm .pivoted to swing on an axis substantially concentricwit-h saidarc;

a threaded carrier member in which said threaded mount is adjustahlysustained by its threads; and a knife hinge connection between said carrier and arm arranged in conjunction with the arm to sustain said carrier in two positions, in one of which the microscope is in its operative positioniover the 'lace of thearc, andlin the other of which is beyo'nd and overlapping the end of the arc.

In testimony whereof I have signed my name to this specification.

EDVARD XV. ARMS. 

